One of the most frequently encountered solid tumours in early childhood is neuroblastoma. It sometimes occurs as early as the first year of life and almost always within the first five or six years. The cells of this tumour start in a part of the nervous system (called the autonomic nervous system) which is located alongside the spinal column, and in the adrenal glands. The adrenal glands are inside the abdomen, just above each kidney. Therefore, tumours can arise in the abdomen, pelvis, chest, or even head but the abdomen is the most common site where the tumour is first found (about two thirds of cases), and the adrenal gland is the site where the tumour has started in more than half of all cases encountered.
The outcome of treatment in childhood neuroblastoma depends on a number of “prognostic factors” (I think this needs to be defined) which are used to determine the likely course of events. For example, the disease is far more curable if it is found in the first year of life than later. The site and the extent of the lump is also significant in deciding whether the cancer can be cured. Other very important factors in deciding whether the cancer can be cured are determined by looking at the blood, the appearance of the cells in the tumour under a microscope, and the genes of the cells within the tumour also. It is very common for neuroblastoma to be widespread by the time a lump is noted, and a number of tests are designed to find out the degree of spread and the various tissues involved. For this reason, x-rays, scans and bone marrow tests are used.
It is not always necessary to operate on a neuroblastoma tumour when the tumour is first found. Although it is essential that some tissue is obtained to be analysed under a microscope and by other special tests, such tissue can sometimes be obtained through a needle from a place such as a bone marrow. The bone marrow is the most frequently involved site of spread for the disease. Once the diagnosis, the extent of the disease, and the prognostic factors are ascertained a treatment programme can be designed.
The treatment of neuroblastoma involves every skill and form of treatment currently available in a specialised centre. We combine the benefits of chemotherapy, radiotherapy, surgical operation and sometimes bone marrow transplantation in order to achieve the best results. Traditionally, many children with neuroblastoma have done very poorly, particularly if the disease is first found when the child is above one year of age and is widespread at diagnosis. However, there are signs of improving results in this group of children. The treatment always begins with several courses of chemotherapy. It is usual to delay the operation for removal of the tumour until the results of chemotherapy have been considered and the tumour is shown to have shrunk satisfactorily. Radiation therapy is then given after the operation to the areas where the surgeon feels some tumour cells may have been left behind. Although the tumour might come back in the same place where the original lump was found, more frequently the danger of recurrence is in another area to which the tumour can spread, such as the bone marrow or bones themselves.
For those children where in the past, the results of treatment have been poor, a bone marrow transplant is now considered. For neuroblastoma, the preferred option is to take some of the patient’s own bone marrow and freeze it down for a time in the laboratory (called autologous transplant). The patient then receives very intensive treatment with both chemotherapy and radiotherapy, designed to kill neuroblastoma cells everywhere in the body. This treatment, however, is also likely to kill the child’s normal bone marrow, without which survival is not possible. Therefore, after this very strong treatment, the bone marrow which had been frozen-down is given back to the patient, so that the patient can again make blood cells, which is the normal function of the bone marrow. The child could not survive this kind of intensive treatment unless some bone marrow were preserved in a frozen state before starting.
A protocol is followed, whereby the type of drugs, the dose and the times at which they will be given (usually courses of drugs are two weeks apart) are decided in advance. After a number of courses, it is important to evaluate how the tumour is shrinking and whether the sites of spread are also showing improvement. Remission is achieved when one can no longer detect any tumour using the usual tests. A remission is clearly not a cure because if nothing further is done the disease will surely recur in most cases. The total treatment programme is designed to make sure that the remission occurs and continues, and then go on to eliminate any remaining tumour by using a combination of all the skills and treatments described above. The whole programme may take a year or more. If the neuroblastoma continues to be in remission and treatment is finally stopped, tests and check-ups continue to look for any possible recurrence and also for potential long-term side-effects of treatment.